scholarly journals Structure and transcription of the Drosophila melanogaster vermilion gene and several mutant alleles

1990 ◽  
Vol 10 (4) ◽  
pp. 1423-1431
Author(s):  
L L Searles ◽  
R S Ruth ◽  
A M Pret ◽  
R A Fridell ◽  
A J Ali

The nucleotide sequence and intron-exon structure of the Drosophila melanogaster vermilion (v) gene have been determined. In addition, the sites of several mutations and the effects of these mutations on transcription have been examined. The major v mRNA is generated upon splicing six exons of lengths (5' to 3') 83, 161, 134, 607, 94, and 227 nucleotides (nt). A minor species of v mRNA is initiated at an upstream site and has a 5' exon of at least 152 nt which overlaps the region included in the 83-nt exon of the major v RNA. The three v mutations, v1, v2, and vk, which can be suppressed by mutations at suppressor of sable, su(s), are insertions of transposon 412 at the same position in exon 1, 36 nt downstream of the major transcription initiation site. Despite the 7.5-kilobase insertion in these v alleles, a reduced level of wild-type-sized mRNA accumulates in suppressed mutant strains. The structure and transcription of several unsuppressible v alleles have also been examined. The v36f mutation is a B104/roo insertion in intron 4 near the splice donor site. A mutant carrying this alteration accumulates a very low level of mRNA that is apparently polyadenylated at a site within the B104/roo transposon. The v48a mutation, which deletes approximately 200 nt of DNA, fuses portions of exons 3 and 4 without disruption of the translational reading frame. A smaller transcript accumulates at a wild-type level, and thus an altered, nonfunctional polypeptide is likely to be synthesized in strains carrying this mutation.(ABSTRACT TRUNCATED AT 250 WORDS)

1990 ◽  
Vol 10 (4) ◽  
pp. 1423-1431 ◽  
Author(s):  
L L Searles ◽  
R S Ruth ◽  
A M Pret ◽  
R A Fridell ◽  
A J Ali

The nucleotide sequence and intron-exon structure of the Drosophila melanogaster vermilion (v) gene have been determined. In addition, the sites of several mutations and the effects of these mutations on transcription have been examined. The major v mRNA is generated upon splicing six exons of lengths (5' to 3') 83, 161, 134, 607, 94, and 227 nucleotides (nt). A minor species of v mRNA is initiated at an upstream site and has a 5' exon of at least 152 nt which overlaps the region included in the 83-nt exon of the major v RNA. The three v mutations, v1, v2, and vk, which can be suppressed by mutations at suppressor of sable, su(s), are insertions of transposon 412 at the same position in exon 1, 36 nt downstream of the major transcription initiation site. Despite the 7.5-kilobase insertion in these v alleles, a reduced level of wild-type-sized mRNA accumulates in suppressed mutant strains. The structure and transcription of several unsuppressible v alleles have also been examined. The v36f mutation is a B104/roo insertion in intron 4 near the splice donor site. A mutant carrying this alteration accumulates a very low level of mRNA that is apparently polyadenylated at a site within the B104/roo transposon. The v48a mutation, which deletes approximately 200 nt of DNA, fuses portions of exons 3 and 4 without disruption of the translational reading frame. A smaller transcript accumulates at a wild-type level, and thus an altered, nonfunctional polypeptide is likely to be synthesized in strains carrying this mutation.(ABSTRACT TRUNCATED AT 250 WORDS)


1984 ◽  
Vol 4 (11) ◽  
pp. 2321-2331
Author(s):  
L J Field ◽  
W M Philbrick ◽  
P N Howles ◽  
D P Dickinson ◽  
R A McGowan ◽  
...  

All inbred strains of mice carry the Ren-1 structural gene, which encodes the renin-1 isozyme, the classical renin activity found in kidneys. In addition, some strains carry a second renin structural gene, Ren-2, which encodes the predominantly expressed submaxillary gland renin isozyme, renin-2. Ren-1 and Ren-2 exhibit markedly different patterns of tissue-specific expression. In an effort to understand the molecular basis for this differential expression, detailed analysis of the genomic sequences corresponding to the Ren-1 and Ren-2 genes, and the transcripts originating from these loci, was undertaken. Sequence analysis of regions proximal to the structural genes indicated the presence of eucaryotic consensus sequences for transcription. These sequence motifs were strongly conserved between Ren-1 and Ren-2. Approximately 150 bases upstream from the major transcription initiation site, significant differences between these genes were apparent, including the presence of a repetitive DNA element in the Ren-2 copy as well as other breaks in homology and sequence curiosities. Strong homology between Ren-1 and Ren-2 resumed at a point ca. 200 bases further upstream on Ren-1. S1 analysis of submaxillary gland and kidney RNA populations indicated that the majority of transcripts initiate at homologous positions on Ren-1 and Ren-2. On a per cell basis, the accumulation of Ren-1 transcripts in the kidney and Ren-2 transcripts in the submaxillary gland are probably equivalent. These results suggest that it is tissue-specific utilization of the homologous start sites that is critical to their differential patterns of expression. Models which can account for this observation are presented. Interestingly, we found a minor fraction of transcripts initiating 5' to the major transcription start site. These transcripts encoded an open reading frame which may add an additional 23 amino acids to the N-terminus of the renin precursor.


1984 ◽  
Vol 4 (11) ◽  
pp. 2321-2331 ◽  
Author(s):  
L J Field ◽  
W M Philbrick ◽  
P N Howles ◽  
D P Dickinson ◽  
R A McGowan ◽  
...  

All inbred strains of mice carry the Ren-1 structural gene, which encodes the renin-1 isozyme, the classical renin activity found in kidneys. In addition, some strains carry a second renin structural gene, Ren-2, which encodes the predominantly expressed submaxillary gland renin isozyme, renin-2. Ren-1 and Ren-2 exhibit markedly different patterns of tissue-specific expression. In an effort to understand the molecular basis for this differential expression, detailed analysis of the genomic sequences corresponding to the Ren-1 and Ren-2 genes, and the transcripts originating from these loci, was undertaken. Sequence analysis of regions proximal to the structural genes indicated the presence of eucaryotic consensus sequences for transcription. These sequence motifs were strongly conserved between Ren-1 and Ren-2. Approximately 150 bases upstream from the major transcription initiation site, significant differences between these genes were apparent, including the presence of a repetitive DNA element in the Ren-2 copy as well as other breaks in homology and sequence curiosities. Strong homology between Ren-1 and Ren-2 resumed at a point ca. 200 bases further upstream on Ren-1. S1 analysis of submaxillary gland and kidney RNA populations indicated that the majority of transcripts initiate at homologous positions on Ren-1 and Ren-2. On a per cell basis, the accumulation of Ren-1 transcripts in the kidney and Ren-2 transcripts in the submaxillary gland are probably equivalent. These results suggest that it is tissue-specific utilization of the homologous start sites that is critical to their differential patterns of expression. Models which can account for this observation are presented. Interestingly, we found a minor fraction of transcripts initiating 5' to the major transcription start site. These transcripts encoded an open reading frame which may add an additional 23 amino acids to the N-terminus of the renin precursor.


Genome ◽  
1993 ◽  
Vol 36 (4) ◽  
pp. 676-685 ◽  
Author(s):  
N. J. Clegg ◽  
I. P. Whitehead ◽  
J. A. Williams ◽  
G. B. Spiegelman ◽  
T. A. Grigliatti

In fission yeast, the product of the cdc2 gene is required both for entry into S phase and mitosis. Homologs of cdc2 have been isolated from a number of metazoans, but in general they have not been amenable to genetic analysis. Here we describe P element transposon tagging of Cdc2 in Drosophila melanogaster and the analysis of 10 Cdc2 mutants. The recessive lethality of Cdc2P is associated with a P element located in the 5′ untranslated region of the gene. Seven other alleles have unique single base pair substitutions in the coding region of Cdc2. One allele, Cdc2B47, is mutated in the splice donor site of exon 1. Most mutations in Cdc2, including the presumptive null allele Cdc2B47, die at the pupal stage, suggesting that the maternally supplied Cdc2 gene product drives earlier cell divisions. The phenotypes of our mutants are consistent with a role for Cdc2 in cell proliferation; however, we did not observe any perturbation of the endoreduplication cycle associated with the acquisition of polyteny.Key words: Cdc2, Drosophila, mutations, sequence.


1984 ◽  
Vol 4 (5) ◽  
pp. 875-882
Author(s):  
M J Imperiale ◽  
J R Nevins

Utilizing deletion mutants of a plasmid containing the adenovirus E2 gene, an E1A-inducible transcription unit, we determined the promoter sequences required for full expression in transient transfection assays. Wild-type expression was obtained from plasmids containing only 79 nucleotides of upstream sequence relative to the transcription initiation site. Removal of an additional nine nucleotides lowered expression 10-fold, and deletion to -59 resulted in near total loss of transcription. Wild-type levels of expression were restored to a -28 deletion mutant by insertion of the sequence from -21 to -262 from the wild-type promoter at the -28 position, in either orientation, even though when inserted in the opposite orientation the relevant sequences were ca. 270 nucleotides upstream from their normal position. Finally, this sequence could be placed at a distance of 4,000 nucleotides from the E2 cap site and still retain near total function. Thus, the E2 promoter element can function independent of orientation and position, properties characteristic of enhancer elements.


1987 ◽  
Vol 7 (6) ◽  
pp. 2046-2051 ◽  
Author(s):  
A D Garcia ◽  
A M O'Connell ◽  
S J Sharp

We constructed deletion-substitution and linker-scanning mutations in the 5'-flanking region of the Drosophila melanogaster 5S RNA gene. In vitro transcription of these templates in Drosophila and HeLa cell extracts revealed the presence of an essential control region (-30 region) located between nucleotides -39 and -26 upstream of the transcription initiation site: deletion of sequences upstream of nucleotide position -39 had no detectable effect on the wild-type level of in vitro transcription, whereas mutations extending between positions -39 and 1 resulted in templates with decreased transcriptional levels; specifically, deletion and linker-scanning mutations in the -34 to -26 region (-30 region) resulted in loss of transcription. The -30 region is essential for transcription and therefore forms part of the Drosophila 5S RNA gene transcription promoter. Compared with the activity of the wild-type gene, mutant 5S DNAs exhibited no impairment in the ability to sequester limiting transcription factors in a template exclusion competition assay. While we do not know which transcription factor(s) interacts with the -30 region, the possible involvement of RNA polymerase III at this region is discussed.


2002 ◽  
Vol 22 (19) ◽  
pp. 6697-6705 ◽  
Author(s):  
Jennifer A. Fairley ◽  
Rachel Evans ◽  
Nicola A. Hawkes ◽  
Stefan G. E. Roberts

ABSTRACT The general transcription factor TFIIB plays a central role in the selection of the transcription initiation site. The mechanisms involved are not clear, however. In this study, we analyze core promoter features that are responsible for the susceptibility to mutations in TFIIB and cause a shift in the transcription start site. We show that TFIIB can modulate both the 5′ and 3′ parameters of transcription start site selection in a manner dependent upon the sequence of the initiator. Mutations in TFIIB that cause aberrant transcription start site selection concentrate in a region that plays a pivotal role in modulating TFIIB conformation. Using epitope-specific antibody probes, we show that a TFIIB mutant that causes aberrant transcription start site selection assembles at the promoter in a conformation different from that for wild-type TFIIB. In addition, we uncover a core promoter-dependent effect on TFIIB conformation and provide evidence for novel sequence-specific TFIIB promoter contacts.


1995 ◽  
Vol 310 (3) ◽  
pp. 757-763 ◽  
Author(s):  
A Magyar ◽  
E Bakos ◽  
A Váradi

A 14 kb genomic clone covering the organellar-type Ca(2+)-ATPase gene of Drosophila melanogaster has been isolated and characterized. The sequence of a 7132 bp region extending from 1.1 kb 5′ upstream of the initiation ATG codon over the polyadenylation signal at the 3′ end has been determined. The gene consists of nine exons including one with an exceptional size of 2172 bp representing 72% of the protein coding region. Introns are relatively small (< 100 bp) except for the 3′ intron which has a size of 2239 bp, an exceptionally large size among Drosophila introns. Five of the introns are in the same positions in Drosophila, Artemia and rabbit SERCA1 Ca(2+)-ATPase genes. There is only one organellar-type Ca(2+)-ATPase gene in the Drosophila genome, as was shown by Southern-blot analysis [Váradi, Gilmore-Hebert and Benz (1989) FEBS Lett. 258, 203-207] and by chromosomal localization [Magyar and Váradi (1990) Biochem. Biophys. Res. Commun. 173, 872-877]. Primer extension and S1-nuclease assays revealed a potential transcription initiation site 876 bp upstream of the translation initiation ATG with a TATA-box 23 bp upstream of this site. Analysis of the 5′ region of the Drosophila organellar-type Ca(2+)-ATPase gene suggests the presence of potential recognition sequences of various muscle-specific transcription factors and shows a region with remarkable similarity to that in the rabbit SERCA2 gene. The tissue distribution of expression of the organellar-type Ca(2+)-ATPase gene has been studied by in situ RNA-RNA hybridization on microscopic sections. A low mRNA abundance can be detected in each tissue of adult flies, suggesting a housekeeping function for the gene. On the other hand a pronounced tissue specificity of expression has also been found as the organellar-type Ca(2+)-ATPase is expressed at a very high level in cell bodies of the central nervous system and in various muscles.


1999 ◽  
Vol 277 (2) ◽  
pp. C225-C232 ◽  
Author(s):  
Hiroyuki Nakaura ◽  
Sachio Morimoto ◽  
Fumi Yanaga ◽  
Masashi Nakata ◽  
Hirofumi Nishi ◽  
...  

A splice donor site mutation in intron 15 of the cardiac troponin T (TnT) gene has been shown to cause familial hypertrophic cardiomyopathy (HCM). In this study, two truncated human cardiac TnTs expected to be produced by this mutation were expressed in Escherichia coli and partially (50–55%) exchanged into rabbit permeabilized cardiac muscle fibers. The fibers into which a short truncated TnT, which lacked the COOH-terminal 21 amino acids because of the replacement of 28 amino acids with 7 novel residues, had been exchanged generated a Ca2+-activated maximum force that was slightly, but statistically significantly, lower than that generated by fibers into which wild-type TnT had been exchanged when troponin I (TnI) was phosphorylated by cAMP-dependent protein kinase. A long truncated TnT simply lacking the COOH-terminal 14 amino acids had no significant effect on the maximum force-generating capability in the fibers with either phosphorylated or dephosphorylated TnI. Both these two truncated TnTs conferred a lower cooperativity and a higher Ca2+ sensitivity on the Ca2+-activated force generation than did wild-type TnT, independent of the phosphorylation of TnI by cAMP-dependent protein kinase. The results demonstrate that the splice donor site mutation in the cardiac TnT gene impairs the regulatory function of the TnT molecule, leading to an increase in the Ca2+ sensitivity, and a decrease in the cooperativity, of cardiac muscle contraction, which might be involved in the pathogenesis of HCM.


1984 ◽  
Vol 4 (5) ◽  
pp. 875-882 ◽  
Author(s):  
M J Imperiale ◽  
J R Nevins

Utilizing deletion mutants of a plasmid containing the adenovirus E2 gene, an E1A-inducible transcription unit, we determined the promoter sequences required for full expression in transient transfection assays. Wild-type expression was obtained from plasmids containing only 79 nucleotides of upstream sequence relative to the transcription initiation site. Removal of an additional nine nucleotides lowered expression 10-fold, and deletion to -59 resulted in near total loss of transcription. Wild-type levels of expression were restored to a -28 deletion mutant by insertion of the sequence from -21 to -262 from the wild-type promoter at the -28 position, in either orientation, even though when inserted in the opposite orientation the relevant sequences were ca. 270 nucleotides upstream from their normal position. Finally, this sequence could be placed at a distance of 4,000 nucleotides from the E2 cap site and still retain near total function. Thus, the E2 promoter element can function independent of orientation and position, properties characteristic of enhancer elements.


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